Bone Health

Impact of Vegetable Protein on Calcium and Bone Metabolism

Karl Insogna, M.D., Professor of Internal Medicine (Endocrinology).

Women are four times more likely than men to suffer from osteoporosis, a condition in which bones become fragile and can break due to loss of mineral and protein content, particularly calcium. Osteoporosis is especially common in older women, and half of all women over the age of 50 with osteoporosis will have a fracture due to the porous bones that characterize this condition. Dr. Insogna is uncovering the role of protein in our diets and the long-term effects on skeletal health. Implications of this work include revised dietary guidelines on protein and calcium intake for bone health. 

Highlighted Study Findings

Diet is a crucial source of necessary protein intake, and appropriate diet may reduce the need for supplements and medications to prevent osteoporosis. One source of protein that has gained popularity is soy.  In fact, many young women have adopted soy protein (vegan) diets and 25% of postmenopausal women consume less than the recommended daily requirement of protein. In this study, Dr. Insogna’s laboratory showed that diets based exclusively on soy (vegetable) protein, rather than animal protein, may actually reduce calcium absorption. The basis for this is being studied further, but this finding raises the question of how to use soy and whether animal protein is required to maintain bone health. These results indicated that the type of protein in our diets has important long-term consequences for skeletal health, and suggests that a diet without (or low in) animal protein may not provide the necessary nutrients to maintain healthy bone.

Inhibiting a Chemical in the Intestine—Usually Associated with Mood—To Reduce Bone Loss

Karl L. Insogna, M.D.

Karl Insogna, M.D., Professor of Internal Medicine (Endocrinology)

The incidence of serious fractures due to the fragile bones of osteoporosis is more common in women than men, and one of every two women over the age of 50 with osteoporosis can expect to have a fracture. Current popular pharmacological interventions include the bisphosphonates, such as Fosamax.  However, these drugs can cause gastrointestinal distress, and joint and muscle aches. There are also more serious emerging concerns with these existing medications, including risks of fractures and cancer. For these reasons, consideration of new pharmacological methods to treat osteoporosis is required. Serotonin is usually thought of as a chemical in the brain that affects mood. However, 95 percent of the serotonin in the body comes from a part of the small intestine. In a wholly unexpected recent discovery, researchers found that this gut-derived serotonin, presumed to be involved in digestion, plays a critical role in regulating bone formation. Dr. Insogna and his colleagues have been at the center of key studies illuminating this connection.

Highlighted Study Findings

Preliminary research indicates that inhibiting serotonin production in the small intestine may promote bone formation, and that a treatment for osteoporosis that acts in this fashion may be possible. In his Program-funded ongoing study, Dr. Insogna is focusing on determining if intestine-derived blood serotonin levels control bone density in the general population, as they do in a previously studied family whose members have unusually strong, dense bones and inherited gene mutations that act to inhibit serotonin in the intestine. The outcome of this work will help determine if such a treatment should be pursued as a new way to treat osteoporosis. The ultimate aim is to develop an intervention to reduce or even prevent bone loss that avoids the negative side effects of current treatments.